A Fact Sheet on Paint Stripping Operations from the Navy

Naval Sea Systems Command
NSWC

Naval Surface Warfare Center
Carderock Division

Navy Water Jet Paint Stripping Program

John Williams
NSWC Carderock - Code 2033
June 1995

Navy High Pressure (HP) Water Jet Paint Removal and Recovery Program

Project Objective: To design, develop & demonstrate a high pressure water jet, automated, full recovery and recycling ship paint removal system with minimal environmental impact.

[See document source for graphic chart.]

Coatings Removal Background

• The largest waste stream from Naval shipyards is the waste generated by dry abrasive blasting.
  
• Executive Order 12856 states that all Federal Agents will reduce toxic emissions by 50% from 1994 to 1999.
  
• Increasingly stringent EPA regulations (Clean Air & Clean Water Acts) have increased the time and cost for coatings removal.
  
• The problems associated with stricter environmental regulations and large volumes of waste from blasting is common throughout the DoD and Industry.

• In 1990 the Air Force MS&T office signed a contract with Pratt & Whitney Water Jet Systems (PWWJS) to develop the Large Aircraft Robotic Paint Stripping (LARPS) System
  
• In 1993 NSWCCD proposed the development of a full recovery and recycling HP water jet paint removal system for ships to OPNAV 04 under Generic Logistics R&D Tech. Demo. (Ranked #1 of 63 proposals)
  
• Air Force modified their contract to include the Navy work, creating a joint program, leveraging research dollars and avoiding duplication
  
• NSWCCD put together a team to monitor the program which includes ONR, CINCPACFLT Maintenance, SURFPAC, Air Force, Army, NSRP, private and public shipyards, NDCEE, paint manufacturers, and National Societies (SSPC/NACE)

Less than 13 months after a contract modification was signed with Pratt & Whitney Waterjet Systems the Navy Demonstration Unit was delivered to Puget Sound Naval Shipyard and demonstrated in front of 70 people.

[See document source for photograph]

How HP Water Jet Demonstration System meets OPNAV Requirements

• Reduces the Volume of Waste Generated
  
  • Reduction from 6,000,000 lbs to 100,000 lbs for the hull of one aircraft carrier
    
  • Eliminates change of waste getting into the environment

• Decrease Cost of Maintenance/Cost Effective Systems
  
  • Eliminates cost for containment system and clean-up

• Recent LHA containment cost $1.4M for dry blasting
  
  • Cost savings from reduced waste disposal costs
    
  • Workers don't need to wear protective equipment

• Increase Maintenance Effectiveness
  
  • Produces a cleaner surface for coatings
    
  • Other drydock activities can be worked in unison
    
  • Reduces manhour requirements

• Improve Warfighting Capability
  
  • Reduce the time for a ship in drydock
    
  • Eliminate contamination of abrasive material into mechanical equipment, jet engines and crews quarters

Navy Water Jet Demonstration System

System Description

System in operation on USS LEFTWICH at Pearl Harbor Naval Shipyard [See document source for photo.]

End Effector

System removing underwater hull paint [See document source for photo.]

Nozzle and Shroud

"Even Energy" 22 orifice nozzle with vacuum recovery shroud [See document source for photo.]

Comm. Nozzle Pattern: Even-Energy Nozzle Pattern [See document source for graphic.]

Manipulator Frame

Manipulator provides compliance to hull for full vacuum recovery with 4.5 by 6.5 foot stripping envelope (a approx. 29 sq. ft. area) [See document source for photo.]

Navy High Pressure Water Jet Demonstration System

Effluent Recovery Subsystem

Paint, debris, heavy metals and surface contaminants are removed and water is purified back to deionized water and returned to the ultra-high pressure pump.

[See document source for illustration.]

Recovered Process Water (Effluent): Clean Stripping Water

Navy Water Jet Demonstration System

Water Analysis

[See document source for three photographs.]

Water Quality (mg/L)

Metal	Incoming	Outgoing
Zinc	13.2	Less than 0.10
Lead	Less than 0.10	Less than 0.10
Barium	17.3	0.14
Selenium	0.20	Less than 0.10
Copper	19.7	0.11
Nickel	0.39	Less than 0.10
Chromium	0.39	Less than 0.10

Taken from USS NIMITZ job.

Waste Analysis

The majority of the solids in the waste stream are removed by the vibratory shaker table. This waste is constituted mainly of paint chips.

[See document source for two photographs.]

Waste Analysis

Metal	Qty (mg/kg)
Zinc	6700
Lead	217
Barium	1950
Selenium	less than 20
Copper	296,000
Nickel	329
Chromium	234

Taken from USS NIMITZ job.

USS NIMITZ (CVN 68) Underwater Hull

• Stripped approx. 500 sq. ft. of underwater hull area
  
• 6-coat International FP and BRA Series paint, DFT 30 to 40 mils, excellent condition
  
• Stripping rate of 136 sq. ft./hr.
  
• Selective stripping of 100% antifoulant coating at 20,000 PSI and 202 sq. ft./hr.
  
• Virtually no flash rust

USS NIMITZ (CVN 68) Flight Deck

• Stripped 84 sq. ft. of non-skid from flight deck
  
• Stripping rate of 202 sq. ft./hr.
  
• Virtually no flash rust

USS Sturgeon (SSN 637)

• Tested complete and selective stripping of approx. 2,000 sq. ft.
  
• Removal of 5-coat system at 168 sq ft./hr.
  
• Selective stripping, removing 80% of the coating system at 350 sq. ft./hr.
  
• Preliminary production run, 550 sq. ft. removed in 6 hours
  
• Chloride contamination results showed less than 2 ug/cm2
  
• Original surface profile of 2-3 mils was retained
  
• Virtually no flash rusting

On USS LEFTWICH (DD 984)

• Removed 17,214 sq. ft. of freeboard paint at PHNSY
  
• Removed over 95% of the 5 coat system at a stripping rate of 205 sq. ft. hr.
  
• Surface inspected by NAVSEA 03M and approved to paint over
  
• Virtually no flash rusting
  
• All Surface chloride levels were below 1.3 ug/cm2

System working around containments for sonar dome and organotin removal. [See document source for photo. Caption: Distribution authorized to DOD contractors only, to protect technical information as required by OPNAVINST 55101H per issue date of the document. Other requests will be referred NAVSEA (SEA 09T).]

Results:

• Average removal rate 183 sq. ft. per shift
  
• Best day 921 sq. ft.
  
• Waste reduction reduced from 216,000 lbs if abrasive grit was used to 4,125 lbs with HP water, a 50 to 1 reduction
  
• Containment, disposal, and clean-up costs less than $8,000

On USS Paul Foster (DD 984)

• Removed approx. 11,000 sq. ft. of underwater hull and freeboard paint under RADM M.T. Coyle reduced Maintenance Pilot Program

Navy Water Jet Demonstration System

Surface Contaminants

High pressure water provides an ultra clean surface which virtually removes all surface contaminants. All readings taking for salts on the surface have been below 2 ug/cm2 which is below the new recommended SEA 03M limit.

[See document source for photo]

Need for Hand Held Unit

Demonstration system can not access all areas of ship hull.

[See document source for photo]

Hand Held Unit

• First tested at LBNSY in March of 95
  
• Modifications being made, additional testing to be performed at PSNSY from May to June of 95

Navy High Pressure Water Jet Demonstration System

Advantages and Benefits

• Operational
  
  • Provides cleaner surface for recoating
    
  • Creates a grit-free environment for sailors and equipment

• Financial
  
  • Eliminates containment systems
    
  • Reduces waste, disposal costs and drydock cleanup
    
  • Reduces drydock time for ship
    
  • Lowers manpower requirement
    
  • Ability to selectively strip
    
  • Widespread benefit to all DoD and Commercial Industry

• Environmental
  
  • Reduces waste stream
    
  • Workers not subjected to harmful environment
    
  • Eliminates chance of waste getting into environment

• Bottom Line
  
  • High Pressure water is an environmentally conscious method for paint removal

Navy Water jet Demonstration System

Program Schedule

[See document source for chart]

Contract Mod:
Needs Analysis:
Preliminary/Detail Design:
Fabrication/Procurement
Contractor Testing
Shipyard Demo (PSNSY)
USS LEFTWICH (PHNSY)
Production Enhancement
Proc. of Follow-on Units
USS PAUL FOSTER (LBNSY)
USS SEAHORSE (PSNSY)
USS RESOURCEFUL (GAUM)
USS LINCOLN (PSNSY)